It was a very good weekend for the domestic box office, but a very bad one for 3D.

Cracks are showing again in the rose-tinted glasses as stateside moviegoers largely passed on the opportunity to see "World War Z" and "Monsters University" in extra dimensions.

The 3D box office breakdown for Pixar's "Monster University" was the lowest percentage for any animated title in modern history, while Paramount's "World War Z" represented the weakest 3D showing for an action film, according to a report by B Riley analyst Eric Wold.

Only 31 percent of “Monsters University”'s $82 million debut came from 3D screenings, while roughly 34 percent of "World War Z”s' $66 million bow came from the format.

In contrast, the previous lowest-grossing 3D action movie, "Captain America: The First Avenger," took 40 percent of its opening grosses from screenings in that format, while Pixar's last animated film, "Brave," earned 34 percent of its domestic opening from 3D.

That's bad news for Hollywood, which is enamored of the surcharge that comes with 3D tickets.

Wold used the lackluster results to downgrade 3D equipment manufacturer RealD's stock from a "buy" to a "neutral" rating and to revise its price target from $19.50 a share to $16.25.

"While we remain optimistic about the long-term global opportunity for the 3D format within theaters, we believe that we may be in the middle of a period of adjustment," Wold wrote.

Some of the sluggish numbers may be a revolt among moviegoers over paying $2 to $3 extra to see a 3D film, while another cause may be a lack of 3D showings. With films like "Star Trek: Into Darkness" and "Man of Steel" also taking up 3D real estate, that left fewer screens available for "World War Z" and Monsters University."

Wold predicted that RealD may need to install more 3D screens to reverse the trend and noted that 3D's contribution to the domestic openings of many event films have stabilized in the 30 percent to 45 percent range. Last weekend's "Man of Steel," for instance, took 41 percent of its $125 million debut from 3D screenings.

"While, we believe consumers are choosier with which movies they will see in 3D (given the increased choices), we continue to believe there are not enough 3D screens to meet scheduling demands and that exhibitors need to more smartly schedule the 2D and 3D showings," Wold wrote.